Revolutionising asthma care cuts blue inhaler reliance and carbon emissions

The Sentinel Project is improving outcomes for asthma patients and reducing carbon emissions.

In the UK, 5.4 million people have asthma. Inhalers are a key treatment for respiratory conditions, with approximately 60 million dispensed in England every year. However, inhalers are not always used in an optimal way, which can lead to asthma not being well controlled and avoidable deaths.

Inhaler emissions also account for approximately 3% of the NHS carbon footprint. The overuse of blue inhalers in particular – known as the ‘reliever’ inhaler – is responsible for 250,000 tonnes of CO₂ equivalent annually.(1)

Professor Michael Crooks is driving change in blue inhaler use to benefit patients, while also cutting carbon emissions
Professor Michael Crooks is driving change in blue inhaler use to benefit patients, while also cutting carbon emissions

The propellant used in these inhalers is responsible for most of the emissions, yet alternative approaches to asthma treatment with a significantly lower carbon footprint exist.

The blue ‘reliever’ inhaler, as the name suggests, is used by people with asthma to relieve symptoms when they occur. While blue reliever inhalers provide short-term relief, they don’t treat the underlying problem in asthma, which is inflammation in the airways in the lung. Frequent use of blue reliever inhalers is therefore associated with poor asthma control and an increased risk of asthma attacks.(2)

Now, The Sentinel Project, led by Professor Michael Crooks at Hull York Medical School and Respiratory Consultant at Hull University Teaching Hospitals NHS Trust is driving change.

In a joint working project supported by AstraZeneca and Hull University Teaching Hospitals NHS Trust, Sentinel is helping to educate and support healthcare professionals and asthma patients to improve asthma treatment with appropriate use of inhalers, helping patients improve their lung health and support the environment.

Asthma research nurse Helene in an asthma clinic with a patient

Asthma research nurse Helena in an asthma clinic with a patient

Supporting patients, supporting the environment

People who have asthma had traditionally had two tiers of treatment: the first is a ‘preventer’ inhaler, which can be used every day to prevent asthma symptoms. This inhaler delivers a steroid to keep down the inflammation and sensitivity in the airways.

The second is a blue ‘reliever’ inhaler you would have seen people use, or used yourself – to deliver a medication that quickly opens the airways. This blue inhaler, formally known as a Short Acting Beta Agonist (or SABA, for short), treats asthma symptoms quickly when they come on. It relaxes the muscles in airways, allowing you to breathe more easily.

If you have an asthma attack, the SABA inhaler can be a lifesaver. However, its overuse can also be harmful. If patients are prescribed 3 or more SABA canisters a year, it can indicate that their asthma is not well controlled, which is associated with an increased risk of asthma attacks and, in some cases, even premature death.(2, 3, 4)

These stark findings prompted respiratory researchers at Hull York Medical School to develop The Sentinel Project: to educate and support healthcare professions and patients about asthma treatment, including the appropriate use of inhalers, to improve the health for the 40,000 people living with asthma in Hull and East Riding of Yorkshire.

When the Sentinel pilot began in 2020, it quickly started to deliver dramatic results, leading to a sudden drop-off in the number of prescribed SABA inhalers, an increase in the use of the ‘preventer’ corticosteroid inhalers, and fewer asthma attacks.

Professor Crooks said, "Immediately the outcomes were really positive; just taking our first primary care network in East Yorkshire as an example, following the implementation of Sentinel they went from being among the top 5% of reliever prescribers nationally to below the national average in the space of just 3 months.”

Since then, Sentinel is now accessible to around a third of primary care networks in England, and up to November 2022, an estimated 44,275 fewer blue inhalers had been issued in Hull alone for the treatment of asthma since the project began. This number is growing rapidly as more practices across England start to implement Sentinel.

Shedding light on the overuse of blue inhalers

NHS guidelines support good asthma care with appropriate use of asthma inhalers. But why were these guidelines not being followed?

The global programme SABA Use In Asthma (SABINA) demonstrated that SABA reliever overuse is a global issue in asthma management; 40% of asthma patients were overusing SABA relievers. (5,6) This prompted Professor Crooks to look at what was happening locally.

Professor Crooks explained, “At the start of The Sentinel Project, Hull and East Yorkshire were among the biggest prescribers of blue reliever inhalers in the country. We could see that there was a potential benefit to be had for patients’ health in reducing reliance on these devices.”

Guidelines had previously largely supported treating asthma by prescribing two inhalers: a steroid-containing ‘preventer’ inhaler, and a separate blue ‘reliever’ SABA inhaler.

This has since been superseded by a preferred way of managing asthma for all but the mildest cases, using a combination of steroid and a long-acting version of the blue inhaler in combination, as opposed to a separate preventer and a reliever.

However, this preferred method of managing asthma didn’t gain traction in prescribing by GPs. The Sentinel Project found that GPs were not necessarily aware of the new way of managing asthma, or they had simply become comfortable with the ‘conventional’ approach to prescribing two inhalers.

Sentinel also found that when patients were prescribed the conventional two inhalers, they were not necessarily using them correctly.

Professor Crooks explained, “From a patient perspective, the blue reliever inhaler is what makes people feel better, because it relaxes the muscle around the airway. It works very quickly.

"So when someone's feeling wheezy and breathless and struggling, they take that inhaler and within a few minutes they feel relief, whereas the steroid ‘preventer’ inhaler doesn't have that immediate effect – it takes days to settle inflammation. So, people don't have that psychological relationship with it.”

This has led to a perfect storm in the overuse of blue inhalers, and the knock-on effect of poorer outcomes on people’s health.

Professor Crooks explained, “It resulted in a vicious cycle of people overusing the SABA ‘reliever’ inhaler, and not using their inhaled steroid ‘preventer’. So we developed The Sentinel Project to try and address this.”

Addressing the overuse of blue inhalers and poor asthma outcomes

In a bid to improve the health of asthma patients in the region, Professor Crooks teamed up with AstraZeneca, Hull University Teaching Hospitals NHS Trust, the Hull and East Riding of Yorkshire CCGs (now the Humber and North Yorkshire ICB), asthma clinicians and patients to develop The Sentinel Project to promote good quality asthma care.

They aimed to educate healthcare professions and patients about the inflammatory nature of asthma, and why the appropriate use of treatment is so important.

Professor Crooks explained, “Crucial to our success was the promotion and use of Maintenance and Reliever Therapy (MART) for appropriate patients.

"MART is an approach to treating asthma that uses the same inhaler as both the preventer and reliever. This approach is well known to reduce the risk of asthma attacks and has the potential to reduce the need for blue reliever inhalers and the environmental impact of asthma and its treatment."

The Sentinel Project is comprised of five components which help to support guideline recommended care for asthma in a structured way, all of which were co-designed with patients and clinicians. These components are:

Health care professional education: A series of resources and pre-recorded presentations that are available through the Sentinel website
Implementation of ‘gold standard’ prescribing practices: The Sentinel signed practices up to these, and provided education resources about how to achieve those and implement them into practice
Targeted reviews for asthma patients overusing SABA: Providing a framework to healthcare professionals for structured asthma reviews based on targeting those with frequent blue reliever inhaler use in the past year
Patient education and support: A series of patient-facing resources and support materials that are available through a patient-facing Sentinel website
Real-time data monitoring and reporting of asthma care metrics: Providing support and feedback to primary care practices about how they can access their own prescribing data and how they can monitor their progress over time

What started as a programme in East Riding of Yorkshire and Hull in 2020 has since quickly gained popularity, and has now been adopted by over 350 primary care networks, which represents over a third of all networks in England.

The team developed Sentinel Plus, a scalable framework based on the original project. This framework can be used and implemented by primary care networks in their own practices.

Professor Crooks explained, “The nice thing about the components for Sentinel is that it's all very packaged and easy to share and cascade. We were seeing significant shifts in practice with significant reductions in SABA use.”

Sentinel Plus also have a champions group, a group of people across the country with an interest in improving asthma care, who are trained in the work and help to implement and share it locally.

Improving asthma management: The results

Analysis from our first PCN have found that more patients were able to manage their asthma well, without having an exacerbation, after the implementation of the new treatment, including those who switched to the new SABA-free, maintenance and reliver therapy (MART).

The Sentinel team looked at 2,571 patients who have asthma. Out of those, 33.6% (864 patients) were reviewed for their asthma, of which 44.7% (386 patients) were switched to MART.

After implementing Sentinel, the researchers found that the number of patients who needed more than three SABA inhalers a year decreased. This was true not only for the patients who underwent the review and switched to MART, but also for the overall asthma population.

During the 24-12 months and 12 months prior to implementation, 45.4% and 46.2% of patients were prescribed three or more SABA inhaler canisters per year. After implementation, this decreased to 23.9%.

For those who had an asthma review, 74.5% and 83.6% were prescribed three or more SABA inhaler canisters per year before implementation, and this decreased to 26.5% after implementation.

And for those who were switched to MART following a review, 76.4% and 86.5% were prescribed three or more SABA inhaler canisters per year before implementation, and this decreased to 16.3% after implementation.

At least 71.5% of patients who were switched to MART were still using it 12 months later, and 86.7% of those patients were no longer using SABA.

The research, Improving asthma care through implementation of the SENTINEL program: findings from the pilot site, has been published in ERJ Open Research.

The full evaluation, covering all PCN’s in Hull, is underway and will provide a full understanding of the impact that SENTINEL has had locally.

Professor Crooks said of the results, “Healthcare professions are taking up Sentinel because they recognise that it's important and they've seen that it can be done.

"The results of our evaluation show that you can tackle SABA over-use in asthma and improve outcomes for your patients, so people feel like they can achieve it in their own practice.”

Climate benefits

The natural consequence of reducing overreliance of SABA inhalers is that there are fewer of these in circulation, resulting in benefits for the environment.

Since the Sentinel programme began in 2020, the overall carbon savings in Hull alone due to switching to dry powder inhalers and reduced healthcare use is the equivalent to approximately 1,240 metric tonnes of carbon emissions, the equivalent of around 1,550 transatlantic flights from Leeds to New York.

This number is growing quickly as more and more practices across England start to implement Sentinel.

Professor Crooks explained, “These blue reliever inhalers are typically metered dose inhalers (MDIs), which are the type of inhaler with the greatest impact on the environment – making up 70% of the carbon footprint of all inhalers in the UK.

"So, as well as improving patients’ health in reducing reliance on these devices, Sentinel delivers a significant environmental benefit too.”

Professor Crooks explained that the NHS Long Term Plan talks about reducing the environmental impact of care.

He added, “The plan specifically talks about the role of inhaled treatments in reducing the impact on the environment.

"Sentinel was an opportunity to improve health outcomes by addressing the overuse of SABA, but we also then benefit the environment. And I think that the environmental benefits really have helped leverage uptake in the programme too.”

Next steps for The Sentinel Project

The researchers are working on the full evaluation now covering all primary care networks across Hull and our pilot site in the East Riding. The researchers have launched a qualitative study, to understand the barriers and facilitators to delivering Sentinel, particularly around maintenance and reliever therapy (MART) in asthma.

The team are also working on the more detailed carbon footprint data, to account for switching from the metered-dose inhalers – which are the ones that contain the propellant gases – to the dry powder inhalers (DPIs) which don't, and have a much lower carbon footprint.

And finally, the researchers are continuing to deliver Sentinel Plus – the national scaling of the original Sentinel Project, to spread their work even further across England.

Professor Crooks said, “Behaviour change takes time, but it also requires us to keep hammering home the message and trying to maintain and sustain it until it becomes routine for people. But the evidence is showing that Sentinel is working, and more and more primary networks want to implement it.”

Professor Crooks added, “Sentinel is much bigger than improving asthma outcomes. It has shown the benefit of collaboration between industry, primary and secondary and tertiary healthcare services, patients, commissioners, academic institutions and broader bodies like the Academic Health Science Network.

"When you bring them together, working with patients, then you can achieve a significant change at scale. Sentinel is an example where collaboration has had a significant local – but also national – impact for the good.”

Resources for patients and healthcare professionals are available on the The SENTINEL Plus website. For more information about Sentinel, please contact Professor Michael Crooks. Professor Crooks is a member of the Clinical Sciences Centre.

References

(1) Wilkinson AJK, Menzies-Gow A, Sawyer M, et al. An assessment of short-acting β2-agonist (SABA) use and subsequent greenhouse gas (GHG) emissions in five European countries and the consequence of their potential overuse for asthma in the U.K. BTS Oral Abstract No: S26. http://dx.doi.org/10.1136/thorax-2020-BTSabstracts.32

(2) Global Initiative for Asthma. (GINA). Available at: https://ginasthma.org/wp-content/uploads/2020/04/Main-pocket-guide_2020_04_03-final-wms.pdf (Last accessed: October 2020).

(3) Price D, et al. NPJ Prim Care Respir Med. 2014:12;24:14009<.

(4) Nwaru BI, et al. Eur Respir J. 2020 Apr 16;55(4):1901872.

(5) Quint JK, et al.; on behalf of SABINA European and North American Study contributors. Short-acting β2-agonist exposure and severe asthma exacerbations: SABINA findings from Europe and North America. J Allergy Clin Immunol Pract 2022; DOI: https://doi.org/10.1016/j.jaip.2022.02.047. Epub ahead of print.

(6) Bateman ED, et al. Short-acting β2-agonist prescriptions are associated with poor clinical outcomes of asthma: the multi-country, cross-sectional SABINA III study. Eur Respir J 2021; Sep 24:2101402. doi: 10.1183/13993003.01402-2021. Epub ahead of print. PMID: 34561293.